docs: def power(a,b):
      '''
      power(a,b) is equivalent to a**b except that, like the neuropythy.util.times function, it
        threads over the earliest dimension possible rather than the latest, as numpy's power function
        and ** syntax do. The power() function also works with sparse arrays; though it must reify
        them during the process.
      '''
      (a,b) = unbroadcast(a,b)
      return cpower(a,b)